Recently, metallocene catalysts have been developed and used for olefinic polymer production, which comprise, as the catalyst component, a transition metal compound having a n-ligand bonded to the center metal element via a group.
To exhibit satisfactory activity, however, the catalysts of that type require a large amount of promoters such as aluminoxanes and the like. Therefore, they are problematic in that the total catalyst costs are inevitably high, and, in addition, the catalyst residue resulting from the promoter used often remains in the polymers produced thereby unfavorably coloring the polymers.
In that situation, techniques of using clay, clay minerals and the like along with the catalysts have been proposed so as to reduce the amount of the promoters to be used along with them (Japanese Patent Laid-Open Nos. 301917/1993, 136047/1994, 164510/1997, 009206/1989, etc.).
At present, however, even these techniques could not as yet provide catalysts having satisfactorily high activity.
The present invention is to provide catalysts for olefin-styrene copolymerization capable of efficiently and inexpensively producing olefin-styrene copolymers, and to provide methods for producing olefin-styrene copolymers.